Matthew Sag

On April 27, 2025, I will be running the London Marathon to raise money for pancreatic cancer research. To donate, please go to 2025tcslondonmarathon.enthuse.com/pf/matthew-sag (if you prefer to donate in your own country, let me know and I'll match with a donation to Pancreatic Cancer UK)

@neal_katyal This post was a little bit cringeworthy, but feedback/practice on demand is definitely an amazing use case for generative AI.

Five months ago, I argued against the President's $4 trillion tariffs at the Supreme Court. In 237 years, the Court had never struck down a sitting President's signature initiative. Legal scholars said it was impossible. Some of my own colleagues said it was impossible. We won. 6-3. But the real story isn't what happened in that courtroom. It's what happened in the months before. And its the subject of my TED talk, coming out tomorrow. I had the best legal team in the nation, especially Colleen Roh Sinzdak, the most outstanding legal strategist I know. Huge thanks, too, go to the Liberty Justice Center (and in particular its fearless and hyper-intelligent leader Sara Albrecht), who organized the client small businesses, as well as to the brave small businesses themselves. I also had four teachers preparing me. A mindset coach who'd worked with Andre Agassi. An improv coach who taught me that "Yes, and" works in Supreme Court arguments the same way it works everywhere else. A meditation coach who taught me stillness. And Harvey. Harvey predicted many of the questions the Justices asked — sometimes almost word for word. Brilliant. Tireless. Occasionally insufferable. Here's the catch: Harvey isn't a person. Harvey is a bespoke AI I built over the last year with a legal AI company, trained on every question every Justice has asked in oral argument for 25 years, and everything they've ever written. Tomorrow, TED releases my talk about what really happened — and what I learned standing at that podium. AI can predict. AI can analyze. What AI cannot do is the one thing that actually won the argument. Connect. Read the room. Hear not just a Justice's words, but her worry — and answer the worry. That is the irreducibly human skill. Find yours. Go deeper. In this age of AI, that's where your edge lives. The talk goes live Thursday, May 7 at 11am ET: go.ted.com/nealkumarkatyal What's the irreducibly human skill in your work — the thing AI can't touch?

The claim that AI models are “just compression” misunderstands both compression and models. Memorization alone does not make GPT, Claude, or Gemini equivalent to MP3s of their training data. More here: matthewsag.com/the-fallacy-of…

I wrote a short post about my new paper, Copyright's Jagged Frontier, forthcoming article in the Duke Law Journal, matthewsag.com/copyrights-jag…. Download it now on SSRN (who still have it marked as under review!?) papers.ssrn.com/sol3/papers.cf…

@ednewtonrex Yes

so if openai uses my work to build an ai model, and that ai model is used against my country in war - that’s fair use, right?

papers.ssrn.com/sol3/papers.cf… Copyright/AI boundary is a jagged frontier. Memorization is complex, its legal implications depend on the interaction of three distinct doctrines—the substantial similarity test, the fair use defense, and secondary liability rules.

matthewsag.com/legal-scholars… Legal Scholars Roundtable on Artificial Intelligence 2026 Call for Papers (details on the website, submit via the google form). Deadline for submission is February 15, 2026. Please repost :)

@technollama Missed that one, waiting for the Australian-American version

Ah the AI Culture Wars, where people try to prove who is more Latin American than thou, lots of gringo cosplaying going on.

A new ruling in Authors Guild v. OpenAI has major implications for copyright law, well beyond artificial intelligence. This is a guest post by @matthewsag, Jonas Robitscher Professor of Law in Artificial Intelligence, Machine Learning and Data Science at Emory University Law School authorsalliance.org/2025/11/10/cop…

The Authors Guild v. OpenAI ruling just set a troubling low bar for "substantial similarity" of fiction summaries. If ChatGPT outputs are infringing, then thousands of Wikipedia plot summaries are next. matthewsag.com/copyright-wint… #CopyrightLaw #AI

An interdisciplinary and nationwide group including @geomblog, @glassboxed, B Cavello, @matthewsag, @SeedAIOrg and many others is behind this important effort. Students at @BrownUniversity & @UTexasLaw and other stakeholders will help vet and share submissions.

After a demo, my verdict: it's ChatGPT in a black turtleneck. Good for firms needing secure doc review & RAG, but law students can already do most of this with existing tools.

Harvey.AI is courting law schools like Westlaw/Lexis once did, but do we really need it? matthewsag.com/do-law-schools…

Claude is resisting being tested on memorization because of copyright. claude.ai/share/60338544…

How should law schools adapt to generative AI? my new paper, AI Policies for Law Schools, proposes a template policy and explains why we should prepare students for legal practice as it will be, not as it was. 📄 papers.ssrn.com/sol3/papers.cf…

@technollama The Economist had some a few months ago. it's 95% streaming and online shopping as I recall

Are there any statistics on what percentage of data centre use is for AI and what is for things like streaming, search, and other non-AI uses? I remember seeing some charts last year but I can't seem to find them any more.

My new post on competition from AI music and what it means matthewsag.com/competition-fr…

Interesting article: Harvey Is Playing A Different Game - Is It Winning? directory.lawnext.com/library/harvey… via @LawNext I don't know anyone who has actually used Harvey. I'd love to hear from you if you do. Is it good? Is it better than ChatGPT? What is it useful for?

Why can't you copyright an AI-generated image that looks creative? My latest explores the "Skater Beagle" puzzle - how generative AI creates genuinely new works from latent space, not remix, but still lacks the human authorship copyright requires. matthewsag.com/skater-beagle-…

51 copyright lawsuits v AI companies in 2.5 years. 3 decisions on fair use, 2 for and 1 against in district court. Still a long way to go. No more fair use decisions likely possible until Spring 2026. Thomson Reuters v ROSS Intelligence is 1st on appeal. Kadrey maybe 2d in 2026

matthewsag.com/drafting-law-s… This might be helpful.